1. Field of the Invention
The present invention relates to a PDP (Plasma Display Panel) and, more particularly, to an optical filter of the PDP and its fabrication method.
2. Description of the Background Art
Lately, the PDP, a TFT-LCD (Thin Layer Transistor-Liquid Crystal Display), an organic EL (ElectroLuminescence), an FED (Field Emission Display) or the like has been developed as a next-generation digital multimedia display device. Among them, the PDP receives much attention in markets with its merits compared to other display devices.
The PDP is a display device using radiation phenomenon generated when 147 nm ultraviolet generated as He+Xe or Ne+Xe gas is discharged excites R, G and B fluorescent materials in discharge cells formed by barrier ribs. The PDP is most expected display device for a large screen of greater than 40 inches thanks to its advantages of facilitation of fabrication according to a simple structure, high luminance, high efficiency, a memory function, high nonlinearity and a wide angular field of greater than 160°.
A discharge cell of a three-electrode AC surface discharge type PDP having such characteristics will now be described.
FIG. 1 is a perspective view showing a discharge cell of a general three-electrode AC surface discharge type PDP.
As shown in FIG. 1, a discharge cell of the PDP is formed by coupling one front plate 10 and a back plate 20 and injecting a discharge gas therebetween.
The front plate 10 includes: an upper glass substrate 11; a transparent electrode 12 and a bus electrode 13 formed on the upper glass substrate 11; an upper dielectric layer 14 formed at the entire surface of the upper glass substrate 11 including the transparent electrode 12 and the bus electrode 13; and a protection layer 15 formed at the entire surface of the upper dielectric layer 14 to protect the upper dielectric layer 14 against plasma discharge.
The back plate 20 includes: a lower glass substrate 25; an address electrode 14 formed on the lower glass substrate 25; a lower dielectric layer 23 formed at the entire surface of the lower glass substrate 25 including the address electrode 24; a barrier rib 22 formed on the lower dielectric layer 23 to form a discharge cell; and a phosphor 21 formed at the entire surface of the lower dielectric layer 23 and the barrier rib 22.
An optical filter is installed at the entire surface of the thusly constructed PDP in order to prevent reflection of an external light, shield near infrared ray, shield electromagnetic wave and enhance a color purity.
A method for fabricating an electromagnetic wave shield layer for shielding electromagnetic wave discharged from the PDP, which constitutes the optical filter of the PDP, in accordance with a conventional art will now be described with reference to FIG. 2.
FIG. 2 is a flow chart of a method for fabricating an electromagnetic wave shield layer of the optical filter of the PDP in accordance with the conventional art.
As shown in FIG. 2, the conventional method for fabricating an electromagnetic wave shield layer of the optical filter of the PDP includes: forming a base film and winding the base film on a rotating roll (step S31); cutting the wound base film into a predetermined size (step S32); depositing a mesh metal on the cut base film (step S33); and patterning the deposited mesh metal to form a mesh film (step S34).
The conventional method for fabricating an electromagnetic wave shield layer of the optical filter of the PDP will be described in detail as follows.
First, the base film is formed and then wound on the rotating roll (step S31). The base film is formed as a metal foil is laminated on polyethylene terephthalate (PET). The base film wound on the rotating roll is cut to a predetermined size (step S32).
Thereafter, the mesh metal is deposited on the base film which has been cut to the predetermined size (step S33), and then patterned through a photolithography process including an exposing and developing process using a photomask and an etching process (step S34). As for the photomask, a transmission part and a blocking part of the photomask differ in its alignment form according to various resolutions, so a bias angle (θ) is controlled according to a type of the photomask.
As the mesh film having a conductive mesh is formed on the base film through the patterning process, the optical filter of the PDP adopting the electromagnetic wave shield layer 300 in accordance with the conventional art is formed.
As mentioned above, the conventional method for fabricating the electromagnetic wave shield layer has the following problem.
That is, whenever the mesh metal is deposited on the base film and patterned in order to control the predetermined bias angle according to various resolutions of the PDP, photomasks corresponding to the various resolutions of the PDP are required.